The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in the present disclosure and are not admitted to be prior art by inclusion in this section.
In 3GPP Long Term Evolution (“LTE”) Release 10 (March 2011) (the “LTE Standard”), a user equipment (“UE”)-specific reference signal (“UE-RS”) may support up to eight transmission layers using two code division-multiplexing (“CDM”) groups. One of the CDM groups may utilize the following set of UE-RS antenna ports: {7, 8, 11, 13}. The other CDM group may utilize the following set of UE-RS antenna ports: {9, 10, 12, 14}.
Pseudo-random sequences generated for UE devices in an LTE cell may be specific to that cell, or “cell-specific.” This generation may involve two possible scrambling code identities (“SCIDs”). In embodiments where multiple user-multi in, multi out (“MU-MIMO”) transmission is implemented, there may be up to four composite layers utilized to transmit data. Each UE device may have either one or two composite layers. However, MU-MIMO transmissions may be transparent to a given UE device. For example, the existence of co-scheduled UE devices may not be indicated through signaling, and mitigation of interference from co-scheduled UE devices may be limited.